Further Investigation of the Delamination Theory of Wear

The wear mechanisms of metals under low-speed sliding conditions have been investigated experimentally in order to check the validity of the delamination theory of wear. The subsurface damage done under the wear track is documented using nine different metals with various chemical compositions and microstructures under an argon atmosphere. The experimental results show that the predominant wear mechanism is the wear by delamination of sheets. The wear sheet is generated by a subsurface crack extending over a distance which is in general, one to two orders of magnitude longer than the diameter of the asperity contact. Voids are nucleated around inclusions during plastic deformation. In metals without inclusions the void nucleation rate is low and so is the wear rate, even when they have very low hardness. All these observations substantiate the predictions of the delamination theory of wear. It is postulated that a tangential load which is greater than that predicted by the adhesion theory can be transmitted by a “plowing” mechanism between the sliding surfaces. A new wear equation is presented, which complements the model presented in a previous paper.